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This is a working repository for development of NMRA DCC Standards, Recommended Practices, Technical Notes, and other documents.
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S-9.1.1.5 Speaker Impedance Definition #14

Closed bakerstu closed 4 years ago

bakerstu commented 4 years ago

This feedback comes from Gil Fuchs:

In line 115, the definition of speaker impedance cannot be left to manufacturers, as the standard should be binding for both the locomotive/main board manufacturer and the decoder manufacturer, yet there is no guarantee of coordination between the two. What this means is that, using this standard (similar to all other S&RP) – a locomotive manufacturer should be able to design a sound locomotive, including a speaker and a main board with a Next18-S socket, which would not be limited in compatibility to specific decoders. That is the definition of interchangeability and the purpose of the DCC standard. By allowing decoder manufacturers to specify any impedance for a speaker, interchangeability is lost.

bakerstu commented 4 years ago

The latest June 18, 2020 draft states: "The impedance of the speaker is 4-8 ohms and must be documented by the decoder manufacturer. (NEXT18-S only)"

This is exactly consistent with RCN-118 and NEM 662. This was a recent change, are we sure the the correct draft revision was reviewed? Does this not satisfy the ask?

This appears to be a duplicate of issue #1. The concerns raised by this issue appear to be already addressed in the June 18, 2020 draft version of S-9.1.1.5 and therefore no changes to the document are required.